Nine people, including two children, injured in seemingly random shooting at Michigan splash pad

Nine people, including two children, were injured in an apparent random mass shooting Saturday at a city park's splash pad in Michigan, authorities said.

One of the victims, an 8-year-old boy, was struck in his head and hospitalized in critical condition, Oakland County Sheriff Michael Bouchard said at a news conference.

The other child struck by gunfire was described as a 4-year-old boy struck in a thigh and stabilized at a hospital, he said.

A third victim, a 39-year-old woman with injuries to her abdomen and leg, was described as being in critical condition at a hospital, the sheriff said. Those three victims are related, Bouchard said.

The other victims, ages 30 to 78, were said to be stable, he said. One set of victims is husband and wife, the sheriff said. One victim is a city employee, he said.

A suspect killed himself at a home in nearby Shelby Township, he said. The man’s identity was unavailable.

The Oakland County Sheriff’s Office said shortly after 5 p.m. the gunman drove up to the Brooklands Plaza Splash Pad, got out of his vehicle, and opened fire, seemingly indiscriminately.

A sergeant monitoring 911 calls coming into the county via new technology heard the 5:11 p.m. report and rushed to the scene, arriving within 2 minutes, Bouchard said.

The gunman was gone, but the sergeant was able to organize a fast medical response, he said.

The suspect used a semiautomatic handgun, appeared to reload at least twice, and fired an estimated 28 rounds, Bouchard said.

The man had no known connection to the victims.

Deputies quickly developed information about a possible suspect's address by examining a handgun at the scene, Bouchard said. Deputies staged outside the Shelby Township home and were joined by a SWAT team, Bouchard said.

After a stretch of time with no communication from the suspect, law enforcement breached the home and used drones to fly through it and determine if there was still a threat, he said.

They spotted the man dead from a self-inflicted gunshot wound, Bouchard said. Nearby, he said, motioning to an image of a semiautomatic rifle on a screen, "this was on the table."

He said it was possible the suspect had two handguns at the splash pad, but that semiautomatic rifle was not noted by witnesses.

The man may have had "mental health challenges," he said after speaking to a relative.

It was a 75-degree day on the eve of Father's Day, and the splash pad had been closed for maintenance for a few days recently, according to a city's website.

"It was fairly crowded," Bouchard said.

Rochester Hills Mayor Bryan K. Barnett said it was a particularly harrowing attack for the circa-1920s suburb about 30 miles north of Detroit.

“It’s a horrible scene when a child is involved,” he said.

Dennis Romero is a breaking news reporter for NBC News Digital.

TJ SwigartMichelle Acevedo contributed.